Electric and hybrid vehicles have recently become a more common sight on roads worldwide. They have one thing in common and that is they all require a large and powerful rechargeable energy storage, also known as a battery. In most such batteries, several battery cells are stacked together to form a battery powerful enough to provide energy for the vehicle to drive for example several tens of kilometers. The battery cells are in most cases mechanically fixed together with a common frame or enclosure to form a single unit which is conveniently mounted in the vehicle. Furthermore, the size of a battery providing sufficient power for driving an electric or hybrid energy is relatively large, whereby the battery cells tend to be closely packed in order to reduce the size of the battery.
However, the highly powerful batteries also produce high amounts of heat when in operation. Therefore, an appropriate cooling system is required for transporting heat away from the battery cells in order to prevent that the battery cells or other parts of the battery are damaged from overheating. The heat may for example be transported away from the battery cells by a liquid coolant passed through a cooling system in thermal contact with the battery cells. Alternatively or complimentary, cooling may be achieved by an air cooling system.
One example of a battery module having a cooling system is disclosed by US2013/0288098. The battery module has battery cells stacked in parallel enclosed in a housing. The stack of battery cells is arranged on a cooling plate, and compressible pads are arranged between the stack of battery cells and the cooling plate. In order to maximize the thermal contact between the battery cells, the pads, and the cooling plates, the battery module may be compressed in the vertical direction perpendicular to the stacking direction of the cells. Thereby, the compressible pads are compressed between the battery cells and the cooling plate.
However, the contact surface between the battery cells and the cooling plate is rather limited since the cooling plates are arranged vertically with respect to the stacking direction of the battery cells, as disclosed by US2013/0288098, thereby also the thermal contact is relatively weak. Furthermore, the compression pads (and compression limiting pads) make the battery module relatively complicated.